An explicit charge-based compact model for strained junctionless square-gate FETs

Abstract An explicit charge-based compact model for a long-channel strained junctionless square-gate FET (JL-SGFET) is presented. The unstrained core model is first developed by solving Poisson’s equation under the parabolic potential approximation, from which an implicit unified charge-control model (UCCM) is derived. Mobile charge densities are obtained analytically using the Lambert W function. The total mobile charge is formulated by decoupling the UCCM into depletion and complementary charge parts, eliminating smoothing functions. Strain effects are then incorporated through modifications to threshold voltage, work function, band gap, electron affinity and mobility. A continuous charge-based drain current is derived by solving the Pao-Sah integral, followed by terminal charge expressions. Comparisons with TCAD simulations show excellent agreement across Ge mole fractions, doping concentrations and device geometries. The model maintains accuracy within $$15\%$$ <mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML"> <mml:mrow> <mml:mn>15</mml:mn> <mml:mo>%</mml:mo> </mml:mrow> </mml:math> error for $$qN_DH_{si}/16\epsilon _{si} &lt; 0.36$$ <mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML"> <mml:mrow> <mml:mi>q</mml:mi> <mml:msub> <mml:mi>N</mml:mi> <mml:mi>D</mml:mi> </mml:msub> <mml:msub> <mml:mi>H</mml:mi> <mml:mrow> <mml:mi>si</mml:mi> </mml:mrow> </mml:msub> <mml:mo>/</mml:mo> <mml:mn>16</mml:mn> <mml:msub> <mml:mi>ϵ</mml:mi> <mml:mrow> <mml:mi>si</mml:mi> </mml:mrow> </mml:msub> <mml:mo>&lt;</mml:mo> <mml:mn>0.36</mml:mn> </mml:mrow> </mml:math> without fitting parameters.